Diestock



L. F. HART Aug. 26, 1924.

DIESTOCK .Filed Aug. 27. 1921 2 sheets-sneu 1 l.. F. HART Aug. 269

DIESTOCK Filed Aug- 27 1921 2 Sheets-Sheet 2- Patented Aug. 26, 1924.

UNITED STATES FTET OFFICE.

LOUIS F. HART, OF OLETELANI),l OHIO, ASSIGNQR- TO 'III-IE HART MANUFACTURING COMPANY, OF CLEVELAND, OHIO, A. CORFORATION OI? OHIO.

DIESTOCK.

Application iled August 2'?, 19m.

T0 all whom it may concern:

Be it known that I, Louis F, HART, a citizen of the United States, and a resident of Cleveland, county of Cuyahoga, and State of Ohio, have invented a new and useful Improvement in Diestocks, of which the following is a speciiication, the principle of the invention being herein explained and the best mode in which I have contemplated applying that principle, so as to distinguish it from other inventions.

The present improved die stock is of the same general type as described and claimed in U. S. Letters Patent No. 1,146,871, issued to me under date of July 20, 1915. Changes in construction, however` have been made with the object of rendering such die stocks more adaptable for use in cutting threads on bolts, such threads not requiring to be tapered. With this end in view, among other things, I have devised detachable centering means which permit the die stock to be operated close up to the head of the bolt or a shoulder thereon. I have also incorporated in the die stock proper means whereby the accurate setting of the individual dies or chasers is insured.

To the accomplishment of the foregoing and related ends, the invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims.

The annexed drawings and the following description set forth in detail certain mechanism embodying the invention, such disclosed means constituting, however, but several of the various mechanical forms in which the principle of the invention may be used.

In said annexed drawings Fig. 1 is a rear elevation of my improved die stock showing the work centering device or chuck as attached; Fig, 2 is an elevational view of such centering device by itself viewed from the opposite side to that shown in Fig. 1; Fig. 3 isv an -axial section of the die stock, the` plane of the section being indicated by the line 3 3, Fig. 1; Fig. 4 `is an axial section corresponding with that of Fig. 8 but showing only the work centering device and this a modified form; Fig. 5 is a front elevational view of the die stock; Fig. 6 is a transverse section taken on' the plane indicated by the line- Sefrial No. 495,981.

(3T-6, Fig. 5; and Fig. 7 is partly a sectional View and partly an end elevation of certain of the elements appearing in Fig. 6.

The main body 1 of the die stock is in general of familiar form, being provided with sockets 2 for the reception of handles 3 as usuall Such body is also provided with set of radial or substantially radial openings 4 (see Figs. 3, 5 and 6) that constitute guides for the Chaser dies 5. Four such dies are shown but it will be understood that the number may be varied in die stocks of a different size or for a different use than the particular one illustrated; also that should it be found desirable to employ the present construction of stock foruse in threading pipe or the like, the threads of such dies may be cut on a taper if desired. Said dies 5 are positioned radially in openings 4.- by means of a cam plate 6 rotatably mounted on the body 1 and formed with a series of cam grooves 7 that engage with pins 8 in the dies as will be readily understood. For the purpose of retaining said cam plate 8 in adjusted position a screw 10 is rotatably supported in the lugs 11 that project upwardly from the. die stock body 1. Threaded upon and oscillatory about said screw 10 is a catch 12 that is capable of transverse adjustment within the space between the two lugs 11 by rotating the screw in one direction or the other, while at the same time said catch is oscillatory about the screw as an axis to engage and disengage a notch 13 in the cam plate. Further details of the construction of this portion of the device will be found described in my aforesaid patent and need not be repeated lhere as they form no part of the vpresent invention.

Where a straight thread is being cut in place of a taper thread the matter of accuracy in size is of greater importance and I accordingly provide in connection with the chaser dies just described a device for insuring accuracy in setting. It is of course extremely diiiicult as well as undesirable, on account of possible binding, to fit the pins S of the dies in the respective cam grooves 7 sc that there will be no lost motion and furthermore, with use, the grooves will tend to wear. For the purpose of setting, one of the dies is providedwith one or more transverse marks 5a and it will lil be obvio-us that if the pin of this die .has some playinitsl groove,it may Inov'e from its set position a trifle when the cutting operation isbegun. AsH shown in Fijgsn,

` 7, l avoid this difficulty by providing a sarinof 14- tlia't' enoaoesv with the marked 1 b D 2D die so as to likewise retain it with its pin 8 in contact with the outer wall of the corresponding groovey 7", Vhile thiis sp-ring may take on various forms, that shown in the gures ini question has been designed with view,y to occupying a minimum space while yet being adequate for the',v purpose, s uch spring consisting of a piece of tempered` wirebent atl one end to form an'veye ll'adaptfed for the reception of' a setscrew lfwhereby the spring is securedtogth-e adjacent po-rtion ot the body l.

The" body or" the spring' adjacent such eye rectly.

lifesat right angles theretoandY projects through; a s'inall opening 16 n(whichprevents the" spring from rotatinguabout `the set screws) alongside the" die in question andl has its .outer Vend lfllb bent at right ,angles toy thebodyso as Vtofengage a, notch' A17 in such.v die.v The spring, it; will Aaccordingly be observed, actsas a torsionspringyto hold the pin8 at all timesagainst the outer wall of the groove 7, as clearly shown i'n Fig. 6.

The adjustment of the cam plate to bring and adapted to` fit aga-inst the rear of the latter,j being securedlin pla'ce by ineans of two capstan headed screws 21 that pass throughA openings in laterally projecting ears 22 o'n such annulus 2O into registering openings inthev socketsk 2 of the main body l of the' die stock. The annulus or ring` 20 is'l provided with.V a. plurality of centering pins or jaws 23,- three being shown, such jaws beinfg'heldA in radial or approximately radial slots 24 formed 1inV theinner faceof the' ring. The jaws 23 are preferably of rectangular cross .section and for, con` venience' in' manufacture-the slots 24 are milled -or otlierwisegcut thro-ugh the inner Wall or theA ring and in` order to' cover over thej portions of such slots that would otherwise be'ex'posed, short section 25 oit-light` f gauge' tubing .is fit-ted" to IJthe interior of the annulus 20` forwardly of the jaws g 23,

It is' s'uficient for thel purpose j it ksuc here is'no" strain imposedy thereon' .ll/Fori the. pareces-f of; manlief restricting vided, such plate being rotatably mounted upon the annulus or ring 20 and having a series of cam grooves 27 that engage with pins` 28 on the respective jaws. A small siet screw 29 serves to prevent the cam plate 'from slipping oit the ring' when the latter is detached from the main body of the die stock, while in the attached condition ot the centering device the cam plate, as clearly shown in Fig. 3, is securely held between such main body and the annulus or ring. Rotation or" the cam plate may of course be effected in any suitable way, the means shown consisting o1 a screw SO rotatably held lugs 3l projecting4 from theannulus., or ring 2O and engaging a series of teethBQ on the camplate forming a segmental'gear.

The modification illustrated in Fig.. 4g relates to the 7form of the centering bloclzswhichare here shownas circular or appro'gii-l mately circula-r in crossse'ction.y .Tl'iisrpermits of the use o t circular openingst which may "be drilled in the annularmember ,37 instead'of the rectangular slots 24. There is accordingly no occasion to use in thisl form the tube-section 25 to'covefrthe eX- posed portions o such slots as inthe-tiret described construction. y

The mode ot operation of mypimproved die stock should be apparent from the foregoing description of its component Iparts and of theirL individual operation.4 ltr-will be noted, however, that by means of the screws 21 ,thecentering device may be. in-

stantly detached in its entirety, from themain body of the die stock so vthat theflatter may be brought close ,up to the headv of af bolt or a' shoulder thereon. When on the contrary no such obstacle is present, it will be desirable to employ the centering device andlthis as a junit is just as readily replaced. Finally the tension spring providedinj conjunction with thiemarled' die 5 which) is used in setting the`- die stock lto cut a thread of desired size' vinsures 'thel accuracy of, such setting at all times.y The form ofthe recess orA notch 17 in the side farce ofthe die 5, and thel manner in which the torsion spring 14: engages therewith, is suchgasy to permit of the ready withdrawal' of the die when it is desired to change one set of such dies for another incutting different sizes. The Vupper end of the spring, however, vwill immediately engage with the notch when the die. is inserted. j ,l Y, p

Qth'er' modes ,of Vapplying the' principle of my invention may be employed instead of the'one explained, change being'madefas regards the mechanism herein disclosed, .pro-

vided the Ymeans stated bya'ny of the follow-c`` ing claims 'or the equivalent of such stated I therefore particularly' point out and distinctly clairn;as my,jinventiongl WN -l In mechanism of the character described, the combination with a main bodymember and dies ad-justably held therein; of an annular member detach'ably 'secured to said body-member, radially adjustable guide blocks in said annular member, and a cam-plate for positioning saidblocks, said cam-plate being rotatably mounted on the face of said annular member designed to Contact with said body-member so as to be held between said two members.

2. In mechanism of the character described, the combination with a main bodymember and dies adjustably held therein; or' an annularl member detachably secured to said body-member, said annular member being formed with approximately radial slots cut in its inner face and intersecting the central opening therein, guide blocks movably held in such slots, a cam-plate for positioning said blocks, and a tube-section tted Within said annular member so as to cover the exposed portions of such slots.

3. In mechanism of the character described, the combination of a body-member; dies movable in said member, one of said dies being marked for setting and having a notch in one of its sides; a cam-plate rotatably secured to one end of said member adapted to position said dies therein; and a torsion spring secured at one end to said member and having its other end bent at an angle to engage the notch in said die so as to resiliently force the latter outwardly against the corresponding element on said plate, said spring also permitting the removal of said die Without the displacement of said bent end.

Signed by me this 23d day of August,

LOUIS F. HART. 

